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/*

 *  linux/arch/or32/kernel/signal.c

 *

 *  or32 version

 *    author(s): Matjaz Breskvar (phoenix@bsemi.com)

 *

 *  derived from cris, i386, m68k, ppc, sh ports.

 *

 *  changes:

 *  18. 11. 2003: Matjaz Breskvar (phoenix@bsemi.com)

 *    initial port to or32 architecture

 *

 *  Based on linux/arch/cris/kernel/signal.c

 *    Copyright (C) 2000, 2001, 2002 Axis Communications AB

 *    Authors:  Bjorn Wesen (bjornw@axis.com)

 *

 */

#include <linux/sched.h>

#include <linux/mm.h>

#include <linux/smp.h>

#include <linux/smp_lock.h>

#include <linux/kernel.h>

#include <linux/signal.h>

#include <linux/errno.h>

#include <linux/wait.h>

#include <linux/ptrace.h>

#include <linux/unistd.h>

#include <linux/stddef.h>

#include <asm/processor.h>

#include <asm/ucontext.h>

#include <asm/uaccess.h>

#include <asm/or32-hf.h>

#define DEBUG_SIG 0

#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

/* a syscall in Linux/OR32 is a "l.sys 1" instruction which is 4 bytes */

/* manipulate regs so that upon return, it will be re-executed */

/* We rely on that pc points to the instruction after "l.sys 1", so the

 * library must never do strange things like putting it in a delay slot.

 */

#define RESTART_OR32_SYS(regs) regs->gprs[1] = regs->orig_gpr3; regs->pc -= 4;

int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs);

/*

 * Atomically swap in the new signal mask, and wait for a signal.  Define

 * dummy arguments to be able to reach the regs argument.  (Note that this

 * arrangement relies on old_sigset_t occupying one register.)

 */

int sys_sigsuspend(old_sigset_t mask, long r4, long r5, long mof,

                   long srp, struct pt_regs *regs)

{

        sigset_t saveset;

        phx_signal("mask 0x%lx, r4 0x%lx, r5 0x%lx, mof 0x%lx, srp 0x%lx, regs %p",

                   mask, r4, r5, mof, srp, regs);

        mask &= _BLOCKABLE;

        spin_lock_irq(&current->sighand->siglock);

        saveset = current->blocked;

        siginitset(&current->blocked, mask);

        recalc_sigpending();

        spin_unlock_irq(&current->sighand->siglock);

        regs->gprs[1] = -EINTR;

        while (1) {

                current->state = TASK_INTERRUPTIBLE;

                schedule();

                if (do_signal(0, &saveset, regs))

                        /* We will get here twice: once to call the signal

                           handler, then again to return from the

                           sigsuspend system call.  When calling the

                           signal handler, R10 holds the signal number as

                           set through do_signal.  The sigsuspend call

                           will return with the restored value set above;

                           always -EINTR.  */

                        return regs->gprs[1];

        }

}

/* Define dummy arguments to be able to reach the regs argument.  (Note that

 * this arrangement relies on size_t occupying one register.)

 */

int sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, long r5,

                      long mof, long srp, struct pt_regs *regs)

{

        sigset_t saveset, newset;

        phx_signal("unewset %p, sigsetsize 0x%x, r5 0x%lx, mof 0x%lx, srp 0x%lx, regs %p",

                   unewset, sigsetsize, r5, mof, srp, regs);

        /* XXX: Don't preclude handling different sized sigset_t's.  */

        if (sigsetsize != sizeof(sigset_t))

                return -EINVAL;

        if (copy_from_user(&newset, unewset, sizeof(newset)))

                return -EFAULT;

        sigdelsetmask(&newset, ~_BLOCKABLE);

        spin_lock_irq(&current->sighand->siglock);

        saveset = current->blocked;

        current->blocked = newset;

        recalc_sigpending();

        spin_unlock_irq(&current->sighand->siglock);

        regs->gprs[1] = -EINTR;

        while (1) {

                current->state = TASK_INTERRUPTIBLE;

                schedule();

                if (do_signal(0, &saveset, regs))

                        /* We will get here twice: once to call the signal

                           handler, then again to return from the

                           sigsuspend system call.  When calling the

                           signal handler, R10 holds the signal number as

                           set through do_signal.  The sigsuspend call

                           will return with the restored value set above;

                           always -EINTR.  */

                        return regs->gprs[1];

        }

}

int sys_sigaction(int sig, const struct old_sigaction *act,

                  struct old_sigaction *oact)

{

        struct k_sigaction new_ka, old_ka;

        int ret;

        phx_signal("sig %d, old act %p, old oact %p",

                   sig, act, oact);

        if (act) {

                old_sigset_t mask;

                if (verify_area(VERIFY_READ, act, sizeof(*act)) ||

                    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||

                    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))

                        return -EFAULT;

                __get_user(new_ka.sa.sa_flags, &act->sa_flags);

                __get_user(mask, &act->sa_mask);

                siginitset(&new_ka.sa.sa_mask, mask);

        }

        ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);

        if (!ret && oact) {

                if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||

                    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||

                    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))

                        return -EFAULT;

                __put_user(old_ka.sa.sa_flags, &oact->sa_flags);

                __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);

        }

        return ret;

}

int sys_sigaltstack(const stack_t *uss, stack_t *uoss)

{

        struct pt_regs *regs = (struct pt_regs *) &uss;

        phx_signal("uss %p, uoss %p",

                   uss, uoss);

        return do_sigaltstack(uss, uoss, regs->sp);

}

/*

 * Do a signal return; undo the signal stack.

 */

struct sigframe {

        struct sigcontext sc;

        unsigned long extramask[_NSIG_WORDS-1];

        unsigned char retcode[16];  /* trampoline code */

};

struct rt_sigframe {

        struct siginfo *pinfo;

        void *puc;

        struct siginfo info;

        struct ucontext uc;

        unsigned char retcode[16];  /* trampoline code */

};

static int restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)

{

        unsigned int err = 0;

        unsigned long old_usp;

        phx_signal("regs %p, sc %p",

                   regs, sc);

        /* restore the regs from &sc->regs (same as sc, since regs is first)

         * (sc is already checked for VERIFY_READ since the sigframe was

         *  checked in sys_sigreturn previously)

         */

        if (__copy_from_user(regs, sc, sizeof(struct pt_regs)))

                goto badframe;

        /* make sure the U-flag is set so user-mode cannot fool us */

        regs->sr &= ~SPR_SR_SM;

//      __PHX__ FIXME   

//      regs->dccr |= 1 << 8;

        /* restore the old USP as it was before we stacked the sc etc.

         * (we cannot just pop the sigcontext since we aligned the sp and

         *  stuff after pushing it)

         */

        err |= __get_user(old_usp, &sc->usp);

        phx_signal("old_usp 0x%lx", old_usp);

//      __PHX__ REALLY ???

//      wrusp(old_usp);

        regs->sp = old_usp;

        /* TODO: the other ports use regs->orig_XX to disable syscall checks

         * after this completes, but we don't use that mechanism. maybe we can

         * use it now ?

         */

        return err;

badframe:

        return 1;

}

/* Define dummy arguments to be able to reach the regs argument.  */

asmlinkage int sys_sigreturn(long r3, long r4, long r5, long mof,

                             long srp, struct pt_regs *regs)

{

        struct sigframe *frame = (struct sigframe *)regs->sp;

        sigset_t set;

        phx_signal("r3 0x%lx, r4 0x%lx, r5 0x%lx, mof 0x%lx, srp 0x%lx, regs %p (regs->sp 0x%lx)",

                   r3, r4, r5, mof, srp, regs, regs->sp);

        /*

         * Since we stacked the signal on a dword boundary,

         * then frame should be dword aligned here.  If it's

         * not, then the user is trying to mess with us.

         */

        if (((long)frame) & 3)

                goto badframe;

        if (verify_area(VERIFY_READ, frame, sizeof(*frame)))

                goto badframe;

        if (__get_user(set.sig[0], &frame->sc.oldmask)

            || (_NSIG_WORDS > 1

                && __copy_from_user(&set.sig[1], &frame->extramask,

                                    sizeof(frame->extramask))))

                goto badframe;

        sigdelsetmask(&set, ~_BLOCKABLE);

        spin_lock_irq(&current->sighand->siglock);

        current->blocked = set;

        recalc_sigpending();

        /* __PHX__ throw this out */

        phx_signal("SIGPENDING: %d", signal_pending(current));

        spin_unlock_irq(&current->sighand->siglock);

        if (restore_sigcontext(regs, &frame->sc))

                goto badframe;

        /* TODO: SIGTRAP when single-stepping as in arm ? */

        return regs->gprs[1];

badframe:

        force_sig(SIGSEGV, current);

        return 0;

}

/* Define dummy arguments to be able to reach the regs argument.  */

asmlinkage int sys_rt_sigreturn(long r3, long r4, long r5,

                                long mof, long srp, struct pt_regs *regs)

{

        struct rt_sigframe *frame = (struct rt_sigframe *)regs->sp;

        sigset_t set;

        stack_t st;

        phx_signal("r3 0x%lx, r4 0x%lx, r5 0x%lx, mof 0x%lx, srp 0x%lx, regs %p (regs->sp 0x%lx)",

                   r3, r4, r5, mof, srp, regs, regs->sp);

        /*

         * Since we stacked the signal on a dword boundary,

         * then frame should be dword aligned here.  If it's

         * not, then the user is trying to mess with us.

         */

        if (((long)frame) & 3)

                goto badframe;

        if (verify_area(VERIFY_READ, frame, sizeof(*frame)))

                goto badframe;

        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))

                goto badframe;

        sigdelsetmask(&set, ~_BLOCKABLE);

        spin_lock_irq(&current->sighand->siglock);

        current->blocked = set;

        recalc_sigpending();

        spin_unlock_irq(&current->sighand->siglock);

        if (restore_sigcontext(regs, &frame->uc.uc_mcontext))

                goto badframe;

        if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))

                goto badframe;

        /* It is more difficult to avoid calling this function than to

           call it and ignore errors.  */

        do_sigaltstack(&st, NULL, regs->sp);

        return regs->gprs[1];

badframe:

        force_sig(SIGSEGV, current);

        return 0;

}

/*

 * Set up a signal frame.

 */

static int setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,

                            unsigned long mask)

{

        int err = 0;

        unsigned long usp = regs->sp;

        phx_signal("sc %p, regs %p, mask 0x%lx",

                   sc, regs, mask);

        /* copy the regs. they are first in sc so we can use sc directly */

        err |= __copy_to_user(sc, regs, sizeof(struct pt_regs));

        /* Set the frametype to CRIS_FRAME_NORMAL for the execution of

           the signal handler. The frametype will be restored to its previous

           value in restore_sigcontext. */

        //        regs->frametype = CRIS_FRAME_NORMAL;

        /* then some other stuff */

        err |= __put_user(mask, &sc->oldmask);

        err |= __put_user(usp, &sc->usp);

        return err;

}

/* figure out where we want to put the new signal frame - usually on the stack */

static inline void * get_sigframe(struct k_sigaction *ka,

                                  struct pt_regs * regs, size_t frame_size)

{

        unsigned long sp = regs->sp;

        phx_signal("ka %p, regs %p, frame_size 0x%x (sp 0x%lx)",

                   ka, regs, frame_size, sp);

        /* This is the X/Open sanctioned signal stack switching.  */

        if (ka->sa.sa_flags & SA_ONSTACK) {

                if (! on_sig_stack(sp))

                        sp = current->sas_ss_sp + current->sas_ss_size;

        }

        /* make sure the frame is dword-aligned */

        sp &= ~3;

        return (void *)(sp - frame_size);

}

/* grab and setup a signal frame.

 *

 * basically we stack a lot of state info, and arrange for the

 * user-mode program to return to the kernel using either a

 * trampoline which performs the syscall sigreturn, or a provided

 * user-mode trampoline.

 */

static void setup_frame(int sig, struct k_sigaction *ka,

                        sigset_t *set, struct pt_regs * regs)

{

        struct sigframe *frame;

        unsigned long return_ip;

        int err = 0;

        phx_signal("sig %d, ka %p, set %p, regs %p",

                   sig, ka, set, regs);

        frame = get_sigframe(ka, regs, sizeof(*frame));

        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))

                goto give_sigsegv;

        err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);

        if (err)

                goto give_sigsegv;

        if (_NSIG_WORDS > 1) {

                err |= __copy_to_user(frame->extramask, &set->sig[1],

                                      sizeof(frame->extramask));

        }

        if (err)

                goto give_sigsegv;

        /* Set up to return from userspace.  If provided, use a stub

           already in userspace.  */

        if (ka->sa.sa_flags & SA_RESTORER) {

                return_ip = (unsigned long)ka->sa.sa_restorer;

                phx_signal("SA_RESTORER: return_ip 0x%lx", return_ip);

        } else {

                /* trampoline - the desired return ip is the retcode itself */

                return_ip = (unsigned long)&frame->retcode;

                phx_signal("ktrampoline: return_ip 0x%lx", return_ip);

                /* This is l.ori r11,r0,__NR_sigreturn, l.sys 1 */

                err |= __put_user(0xa960        , (short *)(frame->retcode+0));

                err |= __put_user(__NR_sigreturn, (short *)(frame->retcode+2));

                err |= __put_user(0x20000001, (unsigned long *)(frame->retcode+4));

                err |= __put_user(0x15000000, (unsigned long *)(frame->retcode+8));

        }

        if (err)

                goto give_sigsegv;

        /* Set up registers for signal handler */

        regs->pc = (unsigned long) ka->sa.sa_handler;       /* what we enter NOW   */

        regs->gprs[7] = return_ip;                          /* what we enter LATER */

        regs->gprs[1] = sig;                                /* first argument is signo */

        /* actually move the usp to reflect the stacked frame */

        //      wrusp((unsigned long)frame);

        regs->sp=(unsigned long) frame;

        return;

give_sigsegv:

        if (sig == SIGSEGV)

                ka->sa.sa_handler = SIG_DFL;

        force_sig(SIGSEGV, current);

}

static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,

                           sigset_t *set, struct pt_regs * regs)

{

        struct rt_sigframe *frame;

        unsigned long return_ip;

        int err = 0;

        phx_signal("sig %d, ka %p, info %p, set %p, regs %p",

                   sig, ka, info, set, regs);

        frame = get_sigframe(ka, regs, sizeof(*frame));

        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))

                goto give_sigsegv;

        err |= __put_user(&frame->info, &frame->pinfo);

        err |= __put_user(&frame->uc, &frame->puc);

        err |= copy_siginfo_to_user(&frame->info, info);

        if (err)

                goto give_sigsegv;

        /* Clear all the bits of the ucontext we don't use.  */

        err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));

        err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);

        err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

        if (err)

                goto give_sigsegv;

        if (ka->sa.sa_flags & SA_RESTORER) {

                return_ip = (unsigned long)ka->sa.sa_restorer;

                phx_signal("SA_RESTORER: return_ip 0x%lx", return_ip);

        } else {

                /* trampoline - the desired return ip is the retcode itself */

                return_ip = (unsigned long)&frame->retcode;

                phx_signal("ktrampoline: return_ip 0x%lx", return_ip);

                /* This is l.ori r11,r0,__NR_sigreturn, l.sys 1 */

                err |= __put_user(0xa960        , (short *)(frame->retcode+0));

                err |= __put_user(__NR_sigreturn, (short *)(frame->retcode+2));

                err |= __put_user(0x20000001, (unsigned long *)(frame->retcode+4));

                err |= __put_user(0x15000000, (unsigned long *)(frame->retcode+8));

        }

        if (err)

                goto give_sigsegv;

        /* TODO what is the current->exec_domain stuff and invmap ? */

        /* Set up registers for signal handler */

        regs->pc = (unsigned long) ka->sa.sa_handler;  /* what we enter NOW   */

        regs->gprs[7] = return_ip;                          /* what we enter LATER */

        regs->gprs[1] = sig;                                /* first argument is signo */

        regs->gprs[3] = (unsigned long) &frame->info;       /* second argument is (siginfo_t *) */

        regs->gprs[4] = 0;                                  /* third argument is unused */

        /* actually move the usp to reflect the stacked frame */

        //      wrusp((unsigned long)frame);

        regs->sp = (unsigned long)frame;

        return;

give_sigsegv:

        if (sig == SIGSEGV)

                ka->sa.sa_handler = SIG_DFL;

        force_sig(SIGSEGV, current);

}

/*

 * OK, we're invoking a handler

 */

extern inline void

handle_signal(int canrestart, unsigned long sig,

              siginfo_t *info, struct k_sigaction *ka,

              sigset_t *oldset, struct pt_regs * regs)

{

        phx_signal("canrestart %d, sig %ld, ka %p, info %p, oldset %p, regs %p",

                   canrestart, sig, ka, info, oldset, regs);

        phx_signal("(regs->pc 0x%lx, regs->sp 0x%lx, regs->gprs[7] 0x%lx)",

                   regs->pc, regs->sp, regs->gprs[7]);

        /* Are we from a system call? */

        if (canrestart) {

                /* If so, check system call restarting.. */

                switch (regs->gprs[1]) {

                        case -ERESTARTNOHAND:

                                /* ERESTARTNOHAND means that the syscall should only be

                                   restarted if there was no handler for the signal, and since

                                   we only get here if there is a handler, we dont restart */

                                regs->gprs[1] = -EINTR;

                                break;

                        case -ERESTARTSYS:

                                /* ERESTARTSYS means to restart the syscall if there is no

                                   handler or the handler was registered with SA_RESTART */

                                if (!(ka->sa.sa_flags & SA_RESTART)) {

                                        regs->gprs[1] = -EINTR;

                                        break;

                                }

                        /* fallthrough */

                        case -ERESTARTNOINTR:

                                /* ERESTARTNOINTR means that the syscall should be called again

                                   after the signal handler returns. */

                                RESTART_OR32_SYS(regs);

                }

        }

        /* Set up the stack frame */

        if (ka->sa.sa_flags & SA_SIGINFO)

                setup_rt_frame(sig, ka, info, oldset, regs);

        else

                setup_frame(sig, ka, oldset, regs);

        if (ka->sa.sa_flags & SA_ONESHOT)

                ka->sa.sa_handler = SIG_DFL;

        if (!(ka->sa.sa_flags & SA_NODEFER)) {

                spin_lock_irq(&current->sighand->siglock);

                sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);

                sigaddset(&current->blocked,sig);

                recalc_sigpending();

                spin_unlock_irq(&current->sighand->siglock);

        }

}

/*

 * Note that 'init' is a special process: it doesn't get signals it doesn't

 * want to handle. Thus you cannot kill init even with a SIGKILL even by

 * mistake.

 *

 * Also note that the regs structure given here as an argument, is the latest

 * pushed pt_regs. It may or may not be the same as the first pushed registers

 * when the initial usermode->kernelmode transition took place. Therefore

 * we can use user_mode(regs) to see if we came directly from kernel or user

 * mode below.

 */

int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs)

{

        siginfo_t info;

        int signr;

        struct k_sigaction ka;

        check_stack(NULL, __FILE__, __FUNCTION__, __LINE__);

        phx_signal("canrestart %d, oldset %p, regs %p",

                   canrestart, oldset, regs);

        /*

         * We want the common case to go fast, which

         * is why we may in certain cases get here from

         * kernel mode. Just return without doing anything

         * if so.

         */

        if (!user_mode(regs))

                return 1;

        if (!oldset)

                oldset = &current->blocked;

        signr = get_signal_to_deliver(&info, &ka, regs, NULL);

        if (signr > 0) {

                /* Whee!  Actually deliver the signal.  */

                handle_signal(canrestart, signr, &info, &ka, oldset, regs);

                return 1;

        }

        /* Did we come from a system call? */

        if (canrestart) {

                /* Restart the system call - no handlers present */

                if (regs->gprs[1] == -ERESTARTNOHAND ||

                    regs->gprs[1] == -ERESTARTSYS ||

                    regs->gprs[1] == -ERESTARTNOINTR) {

                        RESTART_OR32_SYS(regs);

                }

                if (regs->gprs[1] == -ERESTART_RESTARTBLOCK){

                  /* look at cris port how to handle this */

                  printk("do_signal: (%s:%d): don't know how to handle ERESTART_RESTARTBLOCK\n",

                         __FILE__, __LINE__);

                }

        }

        return 0;

}